Laundry detergent compositions have for many years contained anionic sulphonate or sulphate surfactant, for example, linear alkylbenzene sulphonate (LAS), together with ethoxylated alcohol nonionic surfactants. Examples abound in the published literature. Conventional ethoxylated alcohol nonionic surfactants used in laundry detergent compositions are typically C10–C16 alcohols having an average degree of ethoxylation of 3 to 8.
Agglomeration of insoluble complexes of calcium in hard water due to the reaction of calcium ions with the anionic surfactant is a well known problem, which is usually avoided by the use of a builder, such as STP, or zeolite which removes calcium ions from the wash liquor. Without builder, detergency performance falls significantly as water hardness increases.
It has now surprisingly been found that the combination of anionic surfactant with nonionic surfactants having high hydrophilic/lipophillic balance (HLB) values, can give enhanced stain removal at a wide range of water hardnesses, especially at high water hardness, even when no builder is present.